Wrinkle resistance treatment for cellulosic textile materials



a large excess of formaldehyde.

ilnired States Patent Ofiiice A 3,023,264 Patented Apr. 3, 1962 3,028,264 WRINKLE RESISTANCE TREATMENT FOR CELLULOSIC TEXTILE MATERIALS John G. Erick, J12, New Caz-leans, La., assigner to the United States of America as represented by the Secretary of Agriculture N Drawing. Filed Apr. 2, 1959, Ser. No. 803,806

2 Claims. (Cl. 117--139.4) (Granted under Title 35, US. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to the treatment of textile ma terials. More particularly, the invention relates to the treatment of textile fabrics, composed mainly of cellulose, to impart wrinkle resistance, dimensional stability, and shape-holding properties to the fabric.

It has been found that the objects of the present invention can be achieved by a proper treatment of the cellulosic textile material in the presence of an acidic polymerization catalyst with the monomeric reaction product of cyanuric acid and formaldehyde and then curing the material. Fabric treated in this manner is exceptionally resilient and resistant to wrinkling. In fact, fabrics treated by this method retain the shape in which they were treated, even after launderings. Garments made of such fabric, therefore, can be Washed and retain their original shape and a neat, unwrinkled appearance without the usual ironing or pressing operation. Although the applied material is derived from an organic nitrogen compound, the treated fabric is surprisingly free of any adverse effects after bleaching with hypochlorite agents.

A further advantage of the process of this invention over previously known processes for rendering cellulosic textiles wrinkle-resistant is that the present treatment is resistant to removal by acidic mediums. In prior art processes, the susceptibility to acids often resulted in destruction of the wrinkle-resistant properties of the fabric if the treated fabric was soured under conditions more acidic or otherwise more drastic than those intended to be employed in commercial laundry procedures. Such accidental, overly vigorous souring procedures are not uncommon in practice. The acid stability of the wrinkleresistance treatment described in this invention is such that even intentional strenuous acidic conditions fail to destroy the wrinkle-resistant properties of the treated fabric.

The cyanuric acid-formaldehyde product used for the treatment of the fabric in the process of this invention can be conveniently obtained by the reaction of cyanuric acid and formaldehyde in aqueous media. It is preferred to employ about three moles of formaldehyde for each mole of cyanuric acid in said reaction. An amount of formaldehyde slightly in excess of this preferred quantity can be used, but it is inefiicient and uneconomical to use It is not usually desirable to employ less than three moles of formaldehyde for each mole of cyanuric acid, due to the limited solubility of the cyanuric acid in the absence of an adequate amount of formaldehyde to react with it. The temperature of the reaction between cyanuric acid and formaldehyde can be varied depending on the rapidity of reaction desired. It is generally preferred to conduct the reaction at a temperature ranging from about 20 C. to about 80 C., using a longer reaction time with the lower temperature. For example, a reaction time of about 1 hour at 80 C. is usually adequate, whereas overnight reaction at room temperature is generally employed.

Following completion of the reaction between the cyanuric acid and formaldehyde, the aqueous solution containing the reaction product is diluted to the desired strength for treatment of the ccllulosic material, and an acidic substance or a substance producing acidity at elevated temperatures is-added to the diluted solution to serve as a polymerization catalyst. The concentration of the cyanuric acid-formaldehyde reaction product present in the diluted solution can be varied depending on the particular textile processing conditions used, the type of textile being treated, and the properties desired in the finished textile. It is generally preferred to use about from 6% to 10% by weight of the cyanuric acid-formaldehyde reaction product in the diluted treating solution. In this preferred treating solution, the concentration of reacted cyanuric acid is about from 3% to 6% by weight and of reacted formaldehyde is about from 2% to 5% by weight. A metal salt of a strong mineral acid is a particularly suitable acidic catalyst to add to the diluted treating solution of the process of the present invention. From about 0.5% to about 6% by weight of the acidic catalyst is generally preferred.

Treatment of the cellulosic textile material according to the process of this invention comprises uniformly impregnating (thoroughly wetting) the textile with the abovedescribed diluted treating solution, mechanically removing excess liquid, then drying and curing the goods. All of these steps can be conveniently carried out with conventional textile finishing equipment. The wet, pickup (increase in weight of the textile upon wetting), after mechanically removing excess liquid, should preferably be from about 70 to when using the preferred treatand temperature are not critical, but it is preferable to.

dry the wet textile, adjusted to the desired pickup, at relatively low temperatures, about from 70 to (1., until the textile is dry to the touch. After drying, the textile is cured by subjecting it to a higher temperature, about from to C., for a brief time, usually about from 3 to 5 minutes, to cause reaction of the applied materials. is used with the lower curing temperature.

Following the curing operation, it is preferable to water-wash the treated textile to remove any unreacted materials. The washing operation can be carried out using the procedures and equipment conventionally employed for the washing of textiles. After it is washed and dried, the treated textile has the same appearance as the original untreated textile and its feel is also essentially unchanged; but the treated fabric possesses resiliency, wrinkle resistance, and other desirable properties previ-. ously described. g

In addition to the cyanuric acid-formaldehyde reaction product and the acidic catalyst, the treating solution of the process of this invention may also contain wetting agents, softening agents, thermoplastic polymeric addi tives such as polyethylenes, polyacrylates, 'silicones and the like, and other components commonly included in conventional wrinkle resistance treatments. Such additive materials can produce a further improvement in the wrinkle resistance and shape-holding properties imparted by the treatment.

The process of this invention can be used to treat substantially any hydrophilic fibrous cellulosic material such as cotton, rayon, ramie, jute and the like which can be impregnated with a liquid, dried and cured.

The following examples are illustrative of the details of at least one method of practicing the present invention. All parts and percentages are by weight.

In the curing operation, the longer time A mixture was prepared from 13 parts of cyanuric acid, 22 parts of 36% aqueous formaldehyde solution that had been neutralized by the addition of alkali, and 22 parts of water. The mixture was shaken or stirred until complete dissolution of the insoluble material occurred, and the resultant solution was allowed to stand at room temperature for 16 hours.

A portion of the prepared solution, 21 parts, was diluted with 79 parts of water. In the diluted solution was dissolved 0.5 part of hydrated zinc nitrate. The diluted solution containing the zinc nitrate was used to impregnate cotton print cloth, so that the wet fabric weighed about 1.8 times the weight of the dry fabric (that is, the wet pickup was about 80%). The fabric was dried in an oven at 70 C. for 10 minutes and then heated in an oven at 160 C. for 3 minutes. After the treatment the fabric was washed in a soap or detergent solution, rinsed well in plain water, and dried.

The increase in recovery from wrinkling, as measured by method 5912, Federal Specifications CCC-T-19lb, that was produced by the treatment is shown in the following table.

When the treated fabric was tested for dam-age caused by retained chlorine from bleaching, by method 69-1952 of the American Association of Textile Chemists and Colorists, it was found to lose none of its strength and suffer no discoloration.

Example 2 A solution of the cyanuric acid-formaldehyde product was prepared as in Example 1 from 13 parts of cyanuric acid, 22 parts of 36% formaldehyde solution, and 22 parts of water. A portion of this solution, 21 parts, was mixed with 74 parts water, 0.5 part hydrated zinc nitrate, and parts of an emulsion containing about 30% of polymerized ethylene. This mixture was used to impregnate cotton print cloth to an 80% weight increase (wet pickup). The wet cloth was then pressed with a hot iron to form creases and leave the cloth essentially dry. In this shape, the cloth was heated at 160 C. for 3 minutes. After this treatment, the cloth retained the creases and pressed appearance through machine laundering and drying with no further ironing.

Example 3 Cotton fabric having a wrinkle recovery angle of 176 (warp-Hill) was treated with a cyanuric acid-formaldehyde reaction product as described in Example 1 to give a treated fabric having a wrinkle recovery angle of 290 (warp+fill).

The outstanding stability of the wrinkle resistance treatment to the action of acids was demonstrated as follows: A sample of this treated fabric was immersed in an aqueous solution containing 5% urea and 1.5% phosphoric 4 acid (which solution had a pH of 2.1) at C. for 30 minutes. The sample was removed, rinsed with water, and dried; and on retesting was found to have a wrinkle recovery angle (warp-i-fill) of 268.

Fabric treated by any of the conventional processes for imparting wrinkle resistance, such as the process employing ethyleneurea-formaldehyde condensate, when subjected to the action of the above-described strongly acidic solution, will revert to a fabric having essentially the same wrinkle recovery angle as the original, untreated fabric.

Example 4 Cyanuric acid, 4.4 parts, was added to a neutralized solution prepared from 7.8 parts of 36% aqueous formaldehyde and 10.2 parts of water. The mixture was stirred until the cyanuric acid dissolved completely and was then allowed to stand 16 hours. This solution was diluted with 74.5 parts of water, and 8.0 parts of a 50% solution of magnesium chloride hexahydrate was added.

Cotton print cloth was impregnated with the diluted solution containing magnesium chloride and mechanically expressed to about an 80% increase in weight (wet pickup). The fabric was dried in an oven at 70 C. for 10 minutes and then heated in an oven at 160 C. for 3 minutes. After the treatment the fabric was washed in a detergent solution and rinsed with water. The increase in wrinkle recovery produced by the treatment is shown in the following table.

Wrinkle Recovery Angle, Degrees Warp Fill Original fabric 86 Treated fabric I claim:

1. A process for treating a cellulosic textile material, whereby said material is rendered wrinkle-resistant, dimensionally stable, permanently shaped, and resistant to damaging effects from hypochlorite bleaching agents, comprising: impregnating a celllosic textile material to a wet pickup of about from 70% to with an aqueous solution of about from 6% to 10% by weight of the monomeric reaction product of cyanuric acid and formaldehyde, and about from 0.5% to 6% by weight of an acidic polymerization catalyst; drying the impregnated material; and then curing it at a temperature of from about to C.

2. The process of claim 1 wherein the catalyst is selected from the group consisting of zinc nitrate and magnesium chloride.

References Cited in the file of this patent UNITED STATES PATENTS 2,561,973 Cohen July 24, 1951 2,690,404 Spangler et al Sept. 28, 1954 2,898,238 Van Loo et al Aug. 4, 1959 2,911,326 Haney et al. Nov. 3, 1959 FOREIGN PATENTS 420,525 Great Britain Nov. 26, 1934 

1. A PROCESS FOR TREATING A CELLULOSIC TEXTILE MATERIAL WHEREBY SAID MATERIAL IS RENDERED WRINKLE-RESISTANT, DIMENSIONALLY STABLE, PERMANENTLY SHAPED, AND RESISTANT TO DAMAGING EFFECTS FROM HYPOCHLORITE BLEACHING AGENTS COMPRISING: IMPREGNATING A CELLOSIC TEXTILE MATERIAL TO A WET PICKUP OF ABOUT FROM 70% TO 90% WITH AN AQUEOUS SOLUTION OF ABOUT FROM 6% TO 10% BY WEIGHT OF THE MONOMERIC REACTION PRODUCT OF CYANURIC ACID AND FORMALDEHYDE, AND ABOUT FORM 0.5% TO 6% BY WEIGHT OF AN ACIDIC POLYMERIZATION CATALYST; DRYING THE IMPREGNATED MATERIAL; AND THEN CURING IT AT A TEMPERATURE OF FROM ABOUT 140* TO 160*C. 